Offlining and Onlining in DNx 120. Workflow understanding.

Interesting workflow I'm seeing for a show that I'm not directly involved with, but I work for the same company.
Company is producing a low budget kids show, archive heavy, graphics, major focus on sound design.

So the clips are being AMA linked and then transcoded to dnx 120 for offline editing. To save money and time the plan is to also deliver the episodes from the 120 transcodes. The plan as I see it is to edit in Avid 8.4, grade in Resolve 12, round trip back to Avid and then deliver.

The step before AMA linking is what I am concerned with. Why is it necessary to bring all archive clips into FCP7, assign Reel ID's, export as ProRes 422, and then AMA link the FCP7 exported clips?

I would assume it would be easier to export an ungraded episode out of Avid. Bring the export into Resolve, import an EDL, grade and deliver from Resolve.

If AMA linking, Media Composer does not support any embedded REEL ID anyway - it uses the file name. I also question why the interim step to ProRes if grading the DNxHD material. And when roundtripping AAF to the MXF media (trnasocded) link and conform and pretty straightforward.